Today is Ash Wednesday, which marks the beginning of Lent, a period in which many Christians choose to abstain from meat as a means of conveying contrition. Instead, these individuals often choose to sustain themselves with fish.

I thought this period in which fish enjoys unusual popularity would be an excellent time to discuss seafood in terms of nutrition, safety, and sustainability. Whether you observe Lent or not, fish can be part of a healthful diet…depending on which varieties you choose.

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Nutrition: Omega-3 Fats

Take a walk through the grocery store these days, and you’ll likely find labels proclaiming the omega-3 fatty acid content on everything from eggs to peanut butter to margarine. Indeed, omega-3 fatty acids have become quite trendy in the food industry. These unsaturated fats have enjoyed such popularity due to the benefits they confer on cardiovascular health; some research suggests that EPA and DHA (two kinds of particularly health-promoting omega-3 fatty acids) may prevent blood clots and irregular heartbeats associated with stroke.

Examples of fatty fish that include high amounts of omega-3 fatty acids include salmon, herring, blue fin tuna, anchovies, and mackerel. You can also take fish oil supplements, but the sources of many fish oil capsules are less than ideal in that they may be derived from farmed fish.

Safety: Methylmercury & PCBs

Unfortunately, despite its nutritional benefits, seafood has a few drawbacks when it comes to health. Seafood is often contaminated with a substance called methylmercury—a byproduct of the mercury found in the emissions of coal-burning power plants. Because of its weight, mercury sinks into waterways where it is methylated and absorbed by the creatures living in them. When humans consume large amounts of these contaminated fish, they can experience serious neurocognitive deterioration. Furthermore, in pregnant women methylmercury crosses the placenta and affects the brain of the developing fetus.

Methylmercury levels are highest in large fish, including those very same species that are highest in omega-3 fatty acids—swordfish and mackerel in particular.

Polychlorinated biphenyls (PCBs) present another safety issue when deciding to eat fish. PCBs are the result of chemicals like chlordane, dieldrin, and DDT that have long since been banned but still linger in waterways, affecting the fish population on a massive scale. PCBs are of concern because they cause a vast array of health problems, ranging from reproduction to development to behavior.

PCBs accumulate in fatty tissues, presenting yet another reason why omega-3-rich fish are not as much of a health food as you might think. Farmed fish contain more PCBs than their wild counterparts due to the fact that they are fed fish meal and fish oils.

Sustainability

Now that the message about seafood’s health benefits has reached the public, there is simply not enough fish available to feed that demand. Natural populations of wild fish are decreasing dramatically, thus providing impetus for the expansion of the fish farming industry.

Farmed fish are raised in very different conditions than their wild counterparts. Rather than feeding on other fish lower in the food chain, farmed fish subsist on fish meal pellets that contain high levels of PCBs and sometimes color additives (in salmon).

Bearing all these factors in mind, it’s easy to be overwhelmed when making a decision to buy and eat fish. Fortunately, organizations such as the Monterey Bay Aquarium Seafood Watch have done all the work for you by creating their seafood recommendations. These guides help you choose the most sustainable and safest fish species available by labeling options as “best,” “good,” and “avoid.”

There is a very convenient app to help you with your buying decisions. Click here to download.

Alternatively, you can download a pdf version to cut out and carry with you.

Armed with that information, you can buy seafood to make delicious dishes like these:

Do you like seafood? What are your favorites?

Filed under: Food Guide, Health News, How To, Study Session